TweetFollow Us on Twitter

June 94 - Somewhere in QuickTime

SOMEWHERE IN QUICKTIME

Basic Movie Playback Support

PETER HODDIE


Adding basic QuickTime movie playback support to most applications is simple, often just one day's work. Developers who want to do this turn first to Inside Macintosh: QuickTime , where it says to use a movie controller component. In Inside Macintosh: QuickTime Components,  you find some elementary movie controller code samples, followed by a large reference section. This is usually enough to get started, but there are a few common problems. This column addresses some of them, with special attention to compatibility with future QuickTime releases. It assumes you're familiar with basic QuickTime and movie controller concepts.

OPENMOVIEFILE
All QuickTime movie files contain a movie resource, usually stored in the file's resource fork, and the actual movie data, stored in the file's data fork. To support cross-platform QuickTime movies, QuickTime's Movie Toolbox also allows the movie resource to be stored in the data fork along with the movie's data. (To learn how this is done, see John Wang's Somewhere in QuickTime column in develop  Issue 17.) The usual sequence of calls to load a QuickTime movie from a file is: OpenMovieFile, NewMovieFromFile, CloseMovieFile.

In the common case of the movie resource stored in the resource fork, OpenMovieFile returns a file reference to the resource fork of the movie file, NewMovieFromFile loads the movie resource from that resource fork and creates a QuickTime movie, and CloseMovieFile closes the resource fork.

But if the movie was created on a computer running Microsoft Windows and QuickTime for Windows (using AdobeTM Premiere, for example), the file won't have a resource fork. Still, you can use the exact same sequence of calls. When OpenMovieFile is called, the file reference returned refers to the data fork; NewMovieFromFile loads the movie from the data fork, and CloseMovieFile closes the data fork.

Some developers don't use OpenMovieFile; they use FSpOpenResFile instead. While this works fine with movies made specifically for the Macintosh, it fails miserably otherwise. There's a sample movie with no resource fork, QuickBuck, on this issue's CD, so you can test this situation with your applications.

If you need to know whether OpenMovieFile opened the resource fork or the data fork, you can examine the file reference it returns, as follows:

pascal Boolean IsDataFork(short fileReference)
{
    FCBPBRec    anFCB;
    Str63       fName;

    anFCB.ioVRefNum = 0;
    anFCB.ioRefNum = fileReference;
    anFCB.ioFCBIndx = 0;
    fName[0] = 0;
    anFCB.ioNamePtr = (StringPtr)fName;

    if (PBGetFCBInfoSync(&anFCB) != noErr)
        return false;

    return (anFCB.ioFCBFlags & 0x0200) == 0;
}

NEWMOVIECONTROLLER
When you need a user interface for playing a movie, you should use NewMovieController to create a movie controller appropriate for use with that movie.

A common mistake is to instead use the Component Manager routine FindNextComponent or OpenDefaultComponent to locate a movie controller. This finds the first movie controller in the system's list of registered components. QuickTime has always contained only one movie controller, so this worked fine. However, future versions of QuickTime will almost certainly include other movie controllers, so the first one isn't necessarily the most appropriate one.

To help track down those offending applications that don't use NewMovieController, there's a system extension on this issue's CD which contains a different movie controller. You'll also find a movie, Other Controller Movie, that should  invoke the sample movie controller. If any other movie invokes the sample movie controller, or if Other Controller Movie invokes the standard movie controller, the application you're testing isn't using NewMovieController. This will cause undesirable results in the not-so-distant future.

UPDATE EVENTS
If you use a movie controller in the recommended way (that is, you allow all events to be filtered through MCIsPlayerEvent), it updates all areas of the window covered by the movie and the movie's controls. Usually that's all a window contains, so all update events are completely handled by the movie controller. This works so well that some developers actually forget to support update events at all.

Unfortunately, it's not always so simple. QuickTime movies aren't always rectangular. If the movie is round and the window is rectangular (as in Figure 1), there are areas in the window that are not covered by the movie or the movie controls. Any update events in these areas are the responsibility of the application. [IMAGE 022-025_Somewhere_in_QT_2.GIF]

Figure 1. A nonrectangular movie

For applications using MCIsPlayerEvent, handling update events is easy:

BeginUpdate(theWindow);
EraseRect(&theWindow->portRect);
EndUpdate(theWindow);

This sample code erases all areas of the window besides the movie and its controls. Normally, erasing the portRect of the window would erase the entire window, but MCIsPlayerEvent sets the update region to just the areas it didn't already handle.

If you don't handle update events, things are even worse than you might think. The window won't be updated correctly, but more important, the operating system will keep generating new update events. Update events have a higher priority than idle events, so the system will never generate idle events -- the movie will receive no time to play.

A sample round movie is provided on this issue's CD so that you can test your handling of update events.

KEYSTROKES
The standard movie controller provides for extensive keyboard control from the user but ignores keystrokes by default. They can be enabled with a single line of code:

MCDoAction(mc, mcActionSetKeysEnabled, (void *)true);

You might want to enable keystrokes only under certain circumstances. For example, a word processor might allow the movie controller to receive keystrokes only when a movie is selected. You can use the mcActionSetKeysEnabled action to enable and disable keystrokes as necessary.

MOUSE CLICKS
All applications that use the standard movie controller pass mouse clicks on to the controller. But not all applications pass mouse clicks made on the movie itself. Failure to pass such clicks will cause problems with any future movie controllers that allow the user to interact directly with the contents of the movie. For example, a movie controller might allow the user to pan around the image by dragging on the movie; if mouse clicks aren't passed through, using either MCClick or MCIsPlayerEvent, this feature won't work.

MOVIE CONTROLLER HELP
The standard Apple movie controller is simple enough for most people to understand immediately, but it supports help balloons anyway (future movie controllers might be less obvious). If Balloon Help is turned on, the standard movie controller automatically displays help for its various controls, as well as for the QuickTime movie itself. You don't have to do anything at all for this to work.

A problem can arise if your application puts up its own help balloons. Since QuickTime movies are often embedded in a larger document, the help balloons may conflict. The result is that the movie controller's help balloon alternates with the application's help balloon. (Use Balloon Help with the Scrapbook desk accessory included with QuickTime to see what this looks like.)

The preferred solution is to stop the application from displaying a help balloon when the cursor is over a QuickTime movie or movie control. It's easy to tell whether a given point in a window intersects the movie:

Boolean PointInMovieController(MovieController
        mc, WindowPtr w, Point where)
{
    RgnHandle   rgn;
    Boolean     result = false;

    rgn = MCGetWindowRgn(mc, w);
    if (rgn != nil) {
        result = PtInRgn(where, rgn);
        DisposeRgn(rgn);
    }
    return result;
}

A second solution is to stop the movie controller from displaying its help balloons -- necessary if you want to display your own help for QuickTime movies. To do this, install an action filter on the movie controller. Every action that occurs in the movie controller (play, step, update, key down, and so on) is passed through a single filter function. Through this filter, an application can gain access to all activity that occurs in the movie controller.

The MegaMovies application on this issue's CD provides a window that displays events that pass through the action filter. The action of interest is mcActionShowBalloon. When this action is sent, QuickTime is about to put up a new help balloon. One of the parameters passed to the action filter is a pointer to a Boolean. The filter can set this Boolean to false to tell the movie controller not to show a balloon. The following code fragments show how to install a simple action filter to prevent the movie controller from displaying help balloons.

pascal Boolean noBalloonsActionFilter 
                (MovieController mc, short action, 
                 void *params, long refCon)
{
    if (action == mcActionShowBalloon)
        *(Boolean *)params = false;
    return false;
}

. . .
MCSetActionFilterWithRefCon(mc, 
        &noBalloonsActionFilter, 0);

CURSOR SHAPE
Many applications change the shape of the cursor depending on what it's currently over. The standard movie controller never changes the cursor, but other movie controllers might want to. Unfortunately, many applications need to control the cursor themselves -- when a movie controller changes the cursor, these applications change it back immediately.

A simple solution is for applications to change the cursor only when it's first placed over a movie. (To determine whether a point is over the movie, use PointInMovieController.) After that, let the movie controller control the cursor until it exits the area over the movie. To give the movie controller the opportunity to change the cursor's shape, you must call either MCIsPlayerEvent or MCIdle frequently while the cursor is over the movie, even if the movie is stopped. The sample movie controller on this issue's CD changes the cursor when it's over the movie, providing an easy way to debug such a scheme.

WINDOW ALIGNMENT
A simple way to improve a QuickTime movie's playback performance is to ensure that the movie is at a good location on the screen. The exact definition of a "good location" varies, based on the screen depth and the processor. A typical good location is one where the first pixel of each scan line begins on a long-word boundary. This allows the decompressors to write data in the most efficientway. On slower machines, proper placement can provide the necessary performance improvement to deliver smooth playback.

Fortunately, applications don't have to understand the details of how to find a good location. QuickTime's Image Compression Manager provides routines to position a window at these locations. When you create a window, you can use AlignWindow to move it to a good location before making it visible. If a window is to be moved, AlignScreenRect will modify the chosen location to make it a good location. When the user drags a window, call DragAlignedWindow instead of DragWindow to place the window in a good location. Examples of these calls are shown below.

WindowPtr   w;
Movie       m;
Rect            r;

// Code to create a properly aligned window.
w = GetNewCWindow(128, nil, (WindowPtr)-1);
m = getMovie();
GetMovieBox(m, &r);
AlignWindow(w, false, &r, nil);

// Code to drag a window with a movie in it and
// keep the window aligned properly.
GetMovieBox(m, &r);
DragAlignedWindow(w, theEvent.where, nil, &r, nil);

These alignment routines were added in QuickTime 1.5, so make sure that QuickTime 1.5 or later is installed before you call them.

MOVIE CONTROLLER EDITING
The standard movie controller supports the editing commands Undo, Cut, Copy, Paste, and Clear, but this functionality is turned off by default. To turn it on, call MCEnableEditing as follows:

MCEnableEditing(mc, true);

You can then use movie controller routines to implement editing:

Movie       m = nil;

switch (editMenuSelection) {
    case menuUndo:      MCUndo(mc);
                            break;
    case menuCut:       m = MCCut(mc);
                            break;
    case menuCopy:      m = MCCopy(mc);
                            break;
    case menuPaste: MCPaste(mc, nil);

Now you have to enable and disable the various menu items. You could call MCGetControllerInfo, which returns a long word of flags indicating, among other things, which Edit menu items should be enabled.With QuickTime 1.5, there's an easier way: call MCSetUpEditMenu, and the movie controller will enable and disable the items in the Edit menu for you.

MCSetUpEditMenu(mc, theEvent.modifiers, editMenuHandle);
[IMAGE 022-025_Somewhere_in_QT_3.GIF]

Standard [IMAGE 022-025_Somewhere_in_QT_4.GIF]

Modified


This routine will even change the menu contents if appropriate. For example, Undo becomes Undo Paste if the last movie controller action was Paste; after Undo Paste is chosen, it becomes Redo Paste. What's more, if the user holds down modifier keys when pulling down a menu, other commands change as well. For example, holding down the Option key changes Paste to Add and Clear to Trim. (See Figure 2.)

Figure 2. Standard and modified Edit menus

MCSetUpEditMenu assumes the Edit menu is arranged in the standard way. If yours is nonstandard, you'll need to use MCGetMenuString to obtain the appropriate text for each standard Edit command, and then enable and disable the menu items according to the information from MCGetControllerInfo.

JUST DO IT
It's so easy to add movie playback support that it's often well worth the effort. As long as you keep these few simple things in mind, you shouldn't have any problems, even with future versions of QuickTime.

PETER HODDIE writes code to introduce hard-to-find bugs into QuickTime. In his spare time he writes code to introduce even harder-to-find bugs into QuickTime. *

Thanks to Jim Batson, Ken Doyle, and John Wang for reviewing this column. *

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

TextSoap 8.3.2 - Automate tedious text d...
TextSoap can automatically remove unwanted characters, fix up messed up carriage returns, and do pretty much anything else that we can think of to text. Save time and effort. Be more productive. Stop... Read more
Apple Remote Desktop 3.9 - Remotely cont...
Apple Remote Desktop is the best way to manage the Mac computers on your network. Distribute software, provide real-time online help to end users, create detailed software and hardware reports, and... Read more
Paragraphs 1.1.4 - Writing tool just for...
Paragraphs is an app just for writers. It was built for one thing and one thing only: writing. It gives you everything you need to create brilliant prose and does away with the rest. Features... Read more
Amazon Chime 4.0.5528 - Amazon-based com...
Amazon Chime is a communications service that transforms online meetings with a secure, easy-to-use application that you can trust. Amazon Chime works seamlessly across your devices so that you can... Read more
Apple Final Cut Pro X 10.3.2 - Professio...
Apple Final Cut Pro X is a professional video editing solution.Completely redesigned from the ground up, Final Cut Pro adds extraordinary speed, quality, and flexibility to every part of the post-... Read more
ForkLift 3.0 - Powerful file manager: FT...
ForkLift is a powerful file manager and ferociously fast FTP client clothed in a clean and versatile UI that offers the combination of absolute simplicity and raw power expected from a well-executed... Read more
VueScan 9.5.70 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
SoftRAID 5.5.6 - High-quality RAID manag...
SoftRAID allows you to create and manage disk arrays to increase performance and reliability. SoftRAID allows the user to create and manage RAID 4 and 5 volumes, RAID 1+0, and RAID 1 (Mirror) and... Read more
Sparkle 2.1.0 - $79.99
Sparkle will change your mind if you thought building websites wasn't for you. Sparkle is the intuitive site builder that lets you create sites for your online portfolio, team or band pages, or... Read more
Logic Pro X 10.3.1 - Music creation and...
Logic Pro X is the most advanced version of Logic ever. Sophisticated new tools for professional songwriting, editing, and mixing are built around a modern interface that's designed to get creative... Read more

Blasty Bubs is a colorful Pinball and Br...
QuickByte Games has another arcade treat in the works -- this time it's a mishmash of brick breaking and Pinball mechanics. It's called Blasty Bubs, and it's a top down brickbreaker that has you slinging balls around a board. [Read more] | Read more »
Corsola and Heracross are the new region...
Generation 2 finally launched in Pokémon GO, unleashing a brand new batch of Pokémon into the wild. Even before the update went live people were speculating on how to catch elusive Pokémon like the legendary "dogs", Unknown, and whether or not... | Read more »
The Warlock of Firetop Mountain (Games)
The Warlock of Firetop Mountain 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: An epic adventure through a mysterious mountain filled with monsters, magic and mayhem! “...it looks downright... | Read more »
Fantasy MMORPG MU Origin’s receives a hu...
Developer Webzen are looking to take their highly popular fantasy battler MU Origin to the next level this month, with its most ambitious overhaul yet. The latest update introduces the long sought after Server Arena, new treasure dungeons, and much... | Read more »
RPG Djinn Caster (Games)
RPG Djinn Caster 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: SPECIAL PRICE 38% OFF(USD 7.99 -> USD 4.99)!!!A Fantasy Action RPG of far foreign lands! Summon the Djinns and rise to... | Read more »
Alto's Odyssey gets its first trail...
There's finally video evidence of Alto's Odyssey, the follow up to the 2015 App Store hit, Alto's Adventure. It looks just as soothing and atmospheric as Alto's last outing, but this time players will be journeying to the desert. Whereas Alto's... | Read more »
Last week on Pocket Gamer
What’s going on in the wider world of portable gaming? Each week we ask that question of our sister website Pocket Gamer. The PG team covers iOS gaming, just like 148Apps, but it also strays into the world of Android games and handheld consoles... | Read more »
Pokémon GO Generation 2 evolution guide
At long last, Niantic Labs finally unleashed the Generation 2 Pokémon into the wild. Pokémon GO trainers are scrambling to grab up this new set of 80 Pokémon. There are some special new tricks required to catch all of these new beasties, though.... | Read more »
The best new games we played this week
It feels as though the New Year got off to a creaking start as far as mobile games go, but that's changed over the past few weeks. The last few days alone have seen the debut of a number of wonderful games, so we thought we'd take the time to... | Read more »
Recruit more scallywags and discover new...
Get ready to show off your sea legs all over again in Oceans & Empires’ new grand update, which aims to make the act of rising to the role of seven seas ruler even more fresh and appealing, thanks to a richness of new content on both iOS and... | Read more »

Price Scanner via MacPrices.net

Apple restocks refurbished 2015 and 2016 13-i...
Apple has Certified Refurbished 2015 and 2016 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2016 13″ 1.6GHz/8GB/128GB... Read more
13-inch 2.5GHz MacBook Pro (Apple refurbished...
Apple has Certified Refurbished 13″ 2.5GHz MacBook Pros (MD101LL/A) available for $829, or $270 off original MSRP. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook... Read more
QuickerTek Announces 5TB Apple AC AirPort Tim...
QuickerTek Inc. has announced their new 5TB hard drive upgrade for Apple’s AC AirPort Time Capsule. By customer request, this upgrade also features six external antennas and offers the highest... Read more
Apple Certified Refurbished iMacs available f...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
Apple offering Certified Refurbished Series 1...
Apple is now offering Certified Refurbished Series 1 and Series 2 Apple Watches for 14-16% off MSRP, starting at $229. An Apple one-year warranty is included with each watch. Shipping is free: Series... Read more
1.4GHz Mac mini on sale for $449, save $50
B&H Photo has the 1.4GHz Mac mini on sale for $50 off MSRP including free shipping plus NY sales tax only: - 1.4GHz Mac mini: $449 $50 off MSRP Read more
12-inch Retina MacBooks on sale for $200-$250...
Newegg has the 12″ 1.2GHz Space Gray Retina MacBook (sku MLH82LL/A) on sale for $1349.99 including free shipping. Their price is $250 off MSRP, and it’s the lowest price available for this model.... Read more
13-inch 2.0GHz Space Gray MacBook Pro on sale...
Adorama has the non-Touch Bar 13″ 2.0GHz Space Gray MacBook Pro in stock today for $100 off MSRP. Shipping is free, and Adorama charges NY & NJ sales tax only: - 13″ 2.0GHz MacBook Pro Space Gray... Read more
13-inch Touch Bar MacBook Pros on sale for $1...
B&H Photo has select 2016 Apple 13″ Touch Bar MacBook Pros in stock today and up to $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.9GHz/512GB Touch Bar MacBook... Read more
KSI-1802R SX Disinfect-able Keyboard With Wav...
KSI has unveiled a new, innovative medical keyboard, the KSI-1802R SX, at HIMSS 2017, running February 19-22 in Orlando, Florida. KSI-1802R SX is the only keyboard that combines dual factor... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
*Apple* Technician - nfrastructure (United S...
Let’s Work Together Apple Technician This position is based in Portland, ME Life at nfrastructure At nfrastructure, we understand that our success results from our Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.